Intravenous catheters have been available for many years, but have undergone virtually little or no change all those years, despite certain shortcomings which, though commonly tolerated, have rendered them less than full serviceable for their intended purpose. In general, each comprises a pair of elongated relatively inner and outer cannulae which have longitudinal axes and elongated bores extending therethrough along the axes thereof, and the relatively inner of which cannulae is telescopically engageable in and disengageable from the bore of the relatively outer cannula when the respective cannulae are coaxially aligned with one another along the respective longitudinal axes thereof. The relatively outer cannula has relatively proximal and distal ends spaced apart from one another along the longitudinal axis thereof, an outer periphery circumposed about the longitudinal axis thereof between the respective ends thereof, a cylindrical outline at the outer periphery thereof, and a cylindrical surface circumposed about the longitudinal axis thereof on the cylindrical outline thereof. The relatively inner cannula has a needle-like shank which is telescopically engageable in and through the bore of the relatively outer cannula from the proximal end thereof, and a hilt which is disposed on the shank and adapted to abut the proximal end of the relatively outer cannula when the shank has extended through the bore of the relatively outer cannula to the extent that the shank projects relatively outwardly beyond the distal end of the relatively outer cannula to form a puncturing tip thereon for the catheter. In use, the relatively inner cannula is telescopically engaged in the relatively outer cannula, to form a unitary assembly of the two cannulae, and then while the assembly is held in one hand, the puncturing tip of the relatively inner cannula and the distal end of the relatively outer cannula are bayonetted through the skin of a recipient until the tip and end of the respective cannulae are inserted in a blood vessel below the skin, but carefully kept in line with the path of the blood vessel and maintained at a relatively shallow angle of incidence to the skin so as not to puncture any of the lateral or ventral sides of the blood vessel. Then, while the hilt of the relatively inner cannula is held by the more ulnar fingers and thumb of that one hand, the index finger of the one hand is engaged with the proximal end portion of the relatively outer cannula, and the relatively outer cannula is driven into the puncture in the skin with the index finger, and relatively lengthwise into the blood vessel itself, to advance the distal end portion of the relatively outer cannula into the blood vessel and disengage the relatively outer cannula from the relatively inner cannula and vice versa. This done, the relatively outer cannula is then interconnected with an auxiliary apparatus external to the body of the recipient, for the transmission of a liquid to the vessel, or the transmission of blood from the vessel, or the monitoring of the condition of the blood in some way; and the connection is commonly made by inserting a fitting on a piece of flexible tubing running from the apparatus, into the proximal end portion of the relatively outer cannula, or vice versa, to form a male/female joint between the tubing and the relatively outer cannula. The entire procedure is, of course, a delicate one in that the catheter and the respective components thereof, are diminutive in size, and are difficult to grasp and manipulate during the various steps of the procedure. Also, if the procedure is to be entirely efficacious, the tip of the relatively inner cannula and the distal end of the relatively outer cannula must be inserted in the blood vessel, and the relatively outer cannula advanced within the blood vessel, lengthwise thereof, without the tip or end of either cannula puncturing the lateral or ventral sides of the blood vessel during the installation procedure. And if the installation is to be comfortable to the recipient, not only must the relatively outer cannula be properly installed in the blood vessel lengthwise thereof, without puncturing any of the lateral or ventral sides of the vessel, but in addition, the relatively outer cannula must be secured against being jiggled in the vessel, side to side or up and down thereof, such as when the recipient moves with a lurch, or worse yet, moves in such relationship to the auxiliary apparatus as to cause the connection to swing the proximal end portion of the relatively outer cannula sidewise of the puncture in the dorsal side of the blood vessel. Commonly, the risk of such relative movement between the body of the recipient, on one hand, and the relatively outer cannula, on the other, has been abated in part by securing a strip of adhesive tape over the joint between the tubing and the relatively outer cannula, that is, at the point at which the moment arm of the relatively outer cannula is greatest. But while this strategy has been somewhat effective to prevent relative movement between the two, it has also posed a problem for those who are responsible for the care of the recipient during the indwelling of the catheter. The tubing requires replacing from time to time, and each person responsible for replacing the tubing must first remove the strip of adhesive tape to access the joint for the replacement operation. In addition, a sterile gauze, such as a BANDAID brand of skin attachable protective gauze, is commonly placed over the puncture in the skin of the recipient, to protect it against infection, and while this may be spaced apart from the joint and not interfere with the task of replacing the tubing, it is important that any different technique for securing the catheter in place, not interfere with a decision to replace the gauze also, when replacing the tubing.
Given their diminutive size, catheters are best installed by persons who have nimble fingers and thumbs and the dexterity to effect the installation procedure. The ability to use the fingernail of the index finger as a driver or pusher is also an asset, in that it is common practice to effect the advancement of the relatively outer cannula into the blood vessel, by engaging the proximal end portion of the relatively outer cannula with the fingernail of the index finger, and then "uncoiling" the finger to drive the relatively outer cannula up into the blood vessel lengthwise thereof. Women in particular have more nimble fingers, and are more dexterous with their finger tips. They often can also make a better purchase of things they grasp, particularly small things such as catheters. But many anesthesiologists and surgical assistants, and particularly those of the male gender, have more fleshy fingers and thumbs, and are less agile with their fingers and fingernails. For them, the delicate operation of grasping the catheter, bayonetting it into a blood vessel of a recipient, and then advancing the relatively outer cannula up the length of the blood vessel, is not one they can accomplish with ease. Moreover, their task is further complicated by the fact that the blood vessel commonly chosen for the installation, is a vein adjacent the upper side of one hand of the recipient, and the anesthesiologist or other professional effecting the installation, commonly must grasp that one hand of the recipient with his or her other hand, to steady it and spread the skin, while grasping and manipulating the catheter with his or her one hand during the installation process; and any clumsiness on the part of the professional is an additional irritant to the recipient, particularly when the professional effects the step of advancing the relatively outer cannula up the length of the vein of the recipient, i.e., the most delicate step in the procedure.